In keeping with the show's over-the-top tradition, several of the guest stars will be involved in eyebrow-raising stories. "When you think Catherine Deneuve, you think French murderess. At least I do," creator Ryan Murphy told reporters Tuesday at the Television Critics Association press tour.

And that's just the start of it: "There's a storyline that I've always been obsessed with that I'm like, 'You know what? I'm going to give that to Catherine Deneuve,'" Murphy says. "It's a woman who comes in and wants her husband's cremated ashes put in her breast implants so she can always be close to her husband. ... And then, of course, the question is why does she want to get rid of these ashes? What has she fed her husband? It's that kind of a whodunit."

Shields, meanwhile, will play Christian's therapist, who has problems of her own and "develops a mad, obsessive crush on him," Murphy says.

Despite all the star wattage, though, Murphy says that "Nip/Tuck's" fourth season will return the focus to Sean, Christian and Julia (Joely Richardson) after last season's Carver-fueled plot. Early episodes will deal with the impending birth of Sean and Julia's child, the offer from Hagman's character to buy the business and Christian's realization that his most intimate relationship is, in fact, with Sean.

"This show was always about these three people. Make no mistake," Murphy says. "And the guest stars that come in are here -- their stories, their medical cases are there to thematically tell us what's going on in the lives of these two doctors and with Julia. ... It's never going to be an episode where [guest stars] are in every scene."